How do I know if systemctl daemon-reload needs to be run

Question

Is there a way to know the current running config is outdated? Is there a way to view the current running config and compare it to the file?

It would be valuable for troubleshooting to know what the running config was before running reload. Also valuable if the command would tell me if it actually updated the config.

Answer 1

You can check loaded unit by command systemctl show <unit>.service. As far I know there is no tool to check changes in unit files.

As well you could run this bash command for var in $(systemctl | grep running | awk '{print $1}'); do systemctl status $var | grep "changed on disk" | grep ".service"; done it would show what files has been changed.

Example:

[root@centos-linux atolkachev]# for var in $(systemctl | grep running | awk '{print $1}'); do systemctl status $var | grep "changed on disk" | grep ".service"; done
Warning: nginx.service changed on disk. Run 'systemctl daemon-reload' to reload units.

Answer 2

systemd doesn't provide out of the box support for displaying changed unit files, but you can use a bash script like this:

while read unit; do
    systemctl status $unit 2>&1 | awk '/changed on disk/ {print $2}'
done< <(systemctl list-unit-files | grep \.service | awk '{print $1}')

Answer 3

This line will do systemctl daemon-reload if needs to be run:

for service in $(systemctl | grep running | grep .service | awk '{print $1}'); do ! test "$mayreload" && systemctl status $var 2>&1 | grep -q "changed on disk" && && mayreload=1 && echo reloading systemctl && systemctl daemon-reload ; done

Answer 4

This worked for me:

systemctl [--user] show [unit name] --property=NeedDaemonReload

or

systemctl [--user] show [unit name] | grep NeedDaemonReload=

It will output "NeedDaemonReload=yes" if it need to be reloaded.

If you use the grep method you can change the last part to grep NeedDaemonReload=yes or grep NeedDaemonReload=no to make it output nothing when it doesn't match (easier to use for scripting).

You also may want to run this with CanStart